This invention relates, in general, to semiconductor chip packages, and more particularly to semiconductor packages housing a plurality of thinned semiconductor chips to promote heat dissipation.
Semiconductor manufacturers are continually developing semiconductor chips which are faster and deliver more power to a load. Increasing the speed of a semiconductor device while increasing the power it can deliver are difficult tasks to achieve simultaneously. Other hurdles must be overcome which impact performance even if a processing flow can be developed which meets both speed and power requirements.
One of the main problems in increasing speed and power of a device is the removal of heat generated by the semiconductor chip. High operating temperatures reduce electron and hole mobilities while increasing parasitic resistance values, thereby reducing device performance. It is imperative to operate semiconductor chips at as low a temperature as possible if performance is a critical factor. Semiconductor materials are generally poor thermal conductors, this makes heat removal a difficult process. To promote thermal transfer in high performance semiconductor chips, semiconductor wafers are made as thin as possible. The less semiconductor material the heat has to pass through, the faster it can be removed from the semiconductor chip. Bulk semiconductor wafers purchased to form semiconductor chips are not thin enough to provide adequate thermal transfer. Material is removed by either grinding, chemically thinning, or both to produce a thin semiconductor wafer.
Typically, semiconductor wafer thinning is accomplished during final wafer processing to minimize handling of a thin semiconductor wafer. A thinned semiconductor wafer is extremely fragile. Although at the end of a wafer process cycle, a thinned semiconductor wafer still goes through many wafer process steps in which it must be handled. Final semiconductor chip yields can be impacted severely due to wafer breakage at these final stages. Losing a semiconductor wafer at this stage has additional costs because all the wafer processing steps have been completed. It would be of great benefit if a method could be developed which eliminates handling of the thinned semiconductor wafers thereby increasing wafer yields and lowering manufacturing costs.